Return the product of array elements over a given axis treating Not a
Numbers (NaNs) as ones.

One is returned for slices that are all-NaN or empty.

New in version 1.10.0.

Parameters:

a : array_like

Array containing numbers whose sum is desired. If a is not an
array, a conversion is attempted.

axis : int, optional

Axis along which the product is computed. The default is to compute
the product of the flattened array.

dtype : data-type, optional

The type of the returned array and of the accumulator in which the
elements are summed. By default, the dtype of a is used. An
exception is when a has an integer type with less precision than
the platform (u)intp. In that case, the default will be either
(u)int32 or (u)int64 depending on whether the platform is 32 or 64
bits. For inexact inputs, dtype must be inexact.

out : ndarray, optional

Alternate output array in which to place the result. The default
is None. If provided, it must have the same shape as the
expected output, but the type will be cast if necessary. See
doc.ufuncs for details. The casting of NaN to integer can yield
unexpected results.

keepdims : bool, optional

If True, the axes which are reduced are left in the result as
dimensions with size one. With this option, the result will
broadcast correctly against the original arr.

Returns:

nanprod : ndarray

A new array holding the result is returned unless out is
specified, in which case it is returned.